Modulating the consolidation of spatial memories via enhancement of EEG theta rhythm through audio-visual sensory entrainment

记忆，即随着时间推移存储和检索数据或信息的能力，是人类认知的关键功能。因此，记忆的“巩固”意味着从短期的、相对不稳定的形式过渡到更强健的、长期的形式--持续数天、数月甚至数年。虽然在快速可塑性的初始状态下，特别是新的海马区连接形成时，长期巩固的逐渐过程涉及到海马区-新皮质的相互作用。一个似乎与记忆巩固有关的特殊神经信号，也是我研究的中心，是EEG theta节奏：研究表明，theta振荡的阶段可以调节啮齿类动物的海马区突触可塑性；在人类头皮EEG研究中，也描述了theta振荡和记忆之间的联系。很可能，真正的新皮质和海马theta节律相互作用，并对记忆做出不同的贡献。我在西北大学的主持研究小组和其他人的初步研究都指出了一种很有希望的方法来研究theta相关的记忆处理，通过“感觉夹带”来增强EEG theta节律，即通过在theta频率上应用有节奏的听觉和/或视觉刺激。在此基础上，本课题的研究目标如下：1.建立空间信息记忆巩固与提取的范式。通过双峰同步的视听感觉夹带调制采集后的脑电振荡。分析视听theta夹带对记忆巩固的影响，与Beta夹带和无刺激控制条件进行比较。一个较大的theta与随后对空间记忆的更好回忆有关。习得后知觉夹带的theta振荡导致更好的记忆绩效3.习得后β夹带与记忆绩效无关

Memory, i.e. the capacity to store and retrieve data or information over time, is a key function of human cognition. The “consolidation” of memories thereby denotes the transition from a short-term, relatively unstable form, to a more robust, long-term form – lasting days to months and even years. While in the initial state of rapid plasticity, in particular new hippocampal connections are formed, the gradual process of long-term consolidation involves hippocampal-neocortical interactions.One particular neural signal that seems to be linked to memory consolidation and that is in the center of my study, is the EEG theta rhythm: The phase of theta oscillations was shown to modulate hippocampal synaptic plasticity in rodents; and connections between theta oscillations and memory have also been described in human scalp EEG studies. Probably, both genuine neocortical and hippocampal theta rhythms interact and differentially contribute to memory.Preliminary studies of both my host research group at Northwestern University and others have pointed to a promising method to study theta-related memory processing, by enhancing EEG theta rhythm via “sensory entrainment”, i.e. via application of rhythmic auditory and/or visual stimulation at theta frequency. Based on this preliminary work, my research project aims at the following objectives: 1. Establishing a paradigm examining memory consolidation and retrieval for spatial information2. Modulating post-acquisition EEG oscillations through bimodal synchronous audio-visual sensory entrainment at theta and beta frequencies3. Analyzing the effects of the audio-visual theta entrainment on memory consolidation, in comparison to both the beta entrainment and to a no-stimulation control condition I expect1. a larger theta to be associated with better subsequent recall for spatial memories2. the post-acquisition sensory entrainment of theta oscillations to lead to a better memory performance 3. the post-acquisition beta entrainment not to be related to memory performance